Conventional photographic printing apparatuses for printing color images of a film on photosensitive materials are known comprising a scanner unit, a printing exposure means, and film conveying means. In action, printing requirements including image gray levels are optically read by the scanner and used for controlling exposure light emitted to the film from a light source by means of light modulating filters of three primary colors to yield desired gray levels on a photosensitive material.
More particularly, the scanner unit reads image data and its gray levels with an optical sensor detecting rays of light emitted from a light source which is different from the light source for the printing exposure means, and converts it into an electric signal which is then transmitted to the printing exposure means.
The film of which data of image gray levels has been read is conveyed by the film conveying means to the printing exposure means where it is subjected to printing process. The printing requirements are determined by reading the gray level data of all images of the film, and calculating an average gray level from the gray level data of all the images of the film. An optimum printing data of each frame to be printed is hence obtained with reference to the average gray level.
It is common with the conventional photographic printing apparatus that the films are loaded in the apparatus by manually feeding one by one or automatically feeding a chain of the films which have been spliced with one another and wound on a reel of a film feeder. The film is scanned by the scanner unit disposed along a path of the conveying means and its data is used for the printing procedure through exposure of light.
The manual one-by-one feeding of films is a labor concentrated task in which one film is loaded only after the printing procedure of the preceding film is completed, thus requiring at least one operator for engaging a succession of the feeding actions and not allowing a fully automatic mode of the feeding action.
The spliced film feeding also requires an additional time for splicing the films to one another and causes the printing apparatus to be bulky in size.
With the conventional photographic printing apparatus, the film is separated from its patrone before subjected to the printing process and then, handed back to a user in the form of several separated sheets, each having a small number of frames, stored in a known film holder. This will contribute to no efficient business. If the film is not separated but rolled in the patrone, its storage and handling will be much facilitated for the user.
It is an object of the present invention, for overcoming the foregoing disadvantage of the conventional photographic printing apparatus, to provide an improved photographic printing apparatus capable of storing a plurality of film loaded cartridges in a drum, unloading and transferring them one by one to a printing exposure means for printing, and after the printing, returning and loading back without films being separated from their cartridges or spliced with one another, whereby a sequence of the films in their cartridges can be subjected to the printing and handed back to their owners with ease.